荷电膜渗透传质过程的计算机模拟:一价离子的传递

Computer Simulation on the Transport of Ions Through a Charged Membrane by Percolation Theory: Transport of Monovalent Ions

以渗透理论的方法研究一价离子通过荷电膜的传质机理,用计算机编程模拟一价带电离子通过荷电膜的过程以研究荷电膜中导电性能和荷电组分含量的关系.模拟结果表明,对于二维格栅体系在荷电组分含量为0.4～0.6时,膜导电性能存在渗透突跃现象;而对于三维格栅体系则在0.1～0.2时存在渗透突跃现象,此结果和MontoCarlo的二维、三维随机模拟结果比较接近.由于实际的荷电膜也可看作为三维格栅体系,因此,可用三维格栅体系程序对不同荷电分率膜的电导数据进行拟合,结果表明,对于实际的磺化聚苯硫醚(SPPS)/聚醚砜(PES)共混膜,当荷电组分SPPS的分率达到0.144时,共混膜即会从不良导体变为良导体,显然该值落在理论值0.1～0.2,因此,理论模拟结果与实际荷电膜传质的实验数据相吻合.

The transport of monovalent ions through a charged membrane was investigated by percolation approach. Based on percolation concept and theory, the theoretical simulation was conducted for two-dimension (2D) and three-dimension (3D). The results showed that for 2D lattices there has a obviously skip or percolation threshold with charged components from 0.4 to 0.6, and for 3 D lattices, such value is between 0.1 - 0.2. The simulative results were well conformed to those by Monto Carlo simulation for a random system. A practical charged membrane which prepared from the blends of sulphonated polyphenylene sulfide (SPPS)/poly (ether sulfone) (PES) can be considered as a 3D lattices. The experimental conductivity was related with a 3D simulation and the result showed the membrane has a transition from insulator to conductor at the ratio of charged components SPPS about 0.144. Obviously, this value falls in the range of a theoretical simulation for a 3D lattices.